8.4.10 SIGN

(1) Specification format

scalar-function-SIGN ::= SIGN(target-data)
 
  target-data ::= value-expression

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(2) Explanation of specification format

target-data:

Specifies the numeric data to be processed.

The following rules apply:

• Specify the target data in the form of a value expression. For details about value expressions, see 7.21 Value expression.

• Specify numeric data for the target data. For details about numeric data, see (1) Numeric data in 6.2.1 List of data types.

• You cannot specify a dynamic parameter by itself for the target data.

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(3) Rules

1. The data type of the execution result is determined based on the data type of the target data, as shown in the following table:

   Table 8‒7: Data type of the execution result of the scalar function SIGN

   No.	Data type of target data	Data type of the execution result
   1	BIGINT	BIGINT#
   2	INTEGER	INTEGER
   3	SMALLINT	SMALLINT
   4	DECIMAL(p,s)	DECIMAL(1,0)
   5	NUMERIC(p,s)
   6	DOUBLE PRECISION	DOUBLE PRECISION
   7	FLOAT
   8	REAL	REAL

   #

   If the integer data type format is a legacy format, it will be an INTEGER type.

2. The NOT NULL constraint does not apply to the value of the execution result (the null value is allowed).

3. If the target data is a null value, the execution result will be a null value.

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(4) Example

Example:

Determine whether the values of columns C1 to C3 in table T1 are positive, negative, or zero.

SELECT SIGN("C1"),SIGN("C2"),SIGN("C3") FROM "T1"

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